Islamist police in Saudi Arabia have stormed a Christian prayer meeting and arrested its entire congregation, including women and children, and confiscated their bibles, it has been reported.

The raid was the latest incident of a swingeing crackdown on religious minorities in Saudi Arabia by the country's hard-line Commission for the Promotion of Virtue and Prevention of Vice.

The 28 Christians were said to be worshipping at the home of an Indian national in the eastern city of Khafji, when the police entered the building and took them into custody. They have not been seen or heard from since, raising concerns among human rights groups as to their whereabouts.

Nina Shea, director of the Washington-based Hudson Institute's Center for Religious Freedom, told FoxNews.com: 'Saudi Arabia is continuing the religious cleansing that has always been its official policy.

'It is the only nation state in the world with the official policy of banning all churches.

'This is enforced even though there are over two million Christian foreign workers in that country. Those victimized are typically poor, from Asian and African countries with weak governments.'

Activists are now calling on the U.S. to use its considerable influence in the region to help secure the release of the incarcerated Christians.

U.S. religious congregations are marching to their own drums now more than ever. The National Congregations Study’s latest look at the country’s churches, synagogues, and mosques — the third wave of studies that began in 1998 — finds more congregations:

- Open their doors to gays and lesbians in active membership and in leadership.
- Show racial and ethnic diversity in the pews.
- Encourage hand-waving, amen-shouting, and dancing-in-the-aisles during worship.
- Disconnect from denominational ties, doctrines, and rules that might slow or block change.

The study, released Thursday (September 11), draws on interviews with leaders at 1,331 nationally representative congregations and updates data from 1998 and 2006 studies. Non-Christian congregations were included in the study, but there are too few for statistical analysis by topics.

Duke University sociology professor Mark Chaves, who directed the study, said he was “surprised” by how much the acceptance of gays and lesbians has risen since 2006, the first time the study asked about gay involvement in religious congregational life.

Congregations that “permit full-fledged membership for openly gay or lesbian couples in a committed relationship” climbed to 48 percent in 2012, up from 37 percent in 2006.

Most congregations still draw a line at permitting gays to take leadership positions, though the number of congregations allowing gays in leadership is rising; it stands at 26 percent, up from 18 percent.